Individual ministerial responsibility is where the Minister is responisble for the actions of their department. I'm struggling to think of an example, but I believe the Liam Fox incident would be an ok one.

Collective ministerial responsibility is when cabinet members have to agree in public with everything the Government is doing. They can't sit on Sky News and say "Yea, well, I don't agree with that policy". If they do, they'll either be fired or will have to resign. The Coalition government is a good example of where this hasn't worked, and has for the most part been shelved.